Consuming electronic products are integral to people's lives, such as a smart phone and a panel computer, which are used to handle the daily works and provide end users information. Larger display dimensions of a smart phone or a panel computer are developed to present information with more readable fonts and images. However, a large display reduces portability. Recently, a flexible display is applied to a mobile phone to provide a large screen size and to be also convenient for handling. However, there are problems with the display hinge of such flexible phone.